It may have looked like a form slump from the outside, but Wellington wicketkeeper Luke Ronchi certainly didn't believe so.

Just to emphasise the point, the former Australian gloveman and now Black Caps aspirant feasted on Auckland's bowlers on Eden Park's outer oval yesterday to notch his eighth first-class century.

Thanks to Ronchi's 127 off 124 balls, the Firebirds racked up 380 after being sent in to bat, before Auckland's openers played out a Mark Gillespie maiden over before stumps on the first day of the Plunket Shield match.

Ronchi's second century for Wellington was a while in the making, after he marked his debut with a blistering 111 at Karori Park in March. An unbeaten 36 was his best in six innings in Firebirds colours this season, but the stop-start early season schedule hadn't helped.

"I've been pretty calm about the whole situation. We played two T20s in two weeks and I only faced two balls in each of them. It hasn't been a massive amount of cricket and I still felt I've been hitting the ball well in the nets.

"It was nice to make the most of my chance [yesterday]," Ronchi said.

The Dannevirke-born 31-year-old qualifies for New Zealand selection in January and hoped this was the start of a rich run with the bat. He wasn't going to die wondering yesterday against internationals Michael Bates and Kyle Mills, blasting 21 fours and two sixes.

"That's the way I bat. I'm no good trying to block it or leave it. If I start doing things like that, my mind is not where it needs to be.

"Any hundred's a good one for me and I'm pretty chuffed."

There was some good bounce in the pitch and Ronchi felt the Firebirds could do some damage with the new ball if they toiled hard.

Wellington surprised by omitting Mark Houghton, leaving them without a spinner with Luke Woodcock (impending fatherhood) also absent. Seamer Dane Hutchinson was recalled to a four-pronged pace attack.

Jesse Ryder looked the likely headline grabber early in the day after three failures with the bat. He blazed 72 off 66 balls, including 11 fours and a six, before he became one of impressive left-armer Mitchell McClenaghan's four victims.

Wellington were teetering at 182-5 before English all-rounder Chris Woakes helped Ronchi add 102. Woakes contributed 47 in a tidy first knock.

In Napier, Carl Cachopa's run continued with his third first-class century in four matches.

Cachopa's 123 guided shield leaders Central Districts to 367 for seven at stumps on day one after being sent in by Otago. It was the 26-year-old strokemaker's sixth first-class century, all compiled in the space of seven matches stretching back to March.

Cachopa faced 210 deliveries and hit 18 fours as he and Tarun Nethula added 122 for the seventh wicket at Nelson Park. Nethula topped his previous best first-class score of 58 and was 87 not out at stumps.